A medical fluid coupling and a latching connector for establishing a fluid communication between two systems

ABSTRACT

The disclosure relates to a medical fluid coupling for connecting a fluid line to a connection section of a blood treatment apparatus or for connecting to a connecting adapter. The fluid coupling comprises at least one main body. The main body includes a first latching element with a first section. The first section is designed to be elastically bendable and/or elastically tiltable. The main body may optionally include a second latching element with a second section. At least one of the first latching element and the second latching element comprises a recess for receiving a protrusion of the connection section and/or a protrusion to reach into a recess of the blood treatment apparatus or of the connecting adapter.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national stage entry of InternationalPatent Application No. PCT/EP2016/054306, filed on Mar. 1, 2016, andclaims priority to Application No. DE 10 2015 102 990.1, filed in theFederal Republic of Germany on Mar. 2, 2015. The disclosures of theprior applications are expressly incorporated herein in entirety byreference thereto.

TECHNICAL FIELD

This disclosure relates to a fluid coupling and/or latching connector.It relates further to a system, a blood treatment apparatus or aconnecting adapter, a tube line, and a blood treatment machine

BACKGROUND

Connectors for establishing or providing a fluid communication betweentwo systems, which carry or conduct fluid respectively, are known in theprior art.

SUMMARY

fluid coupling Multiple embodiments of fluid couplings or latchingconnector fluid coupling which are designed to be pushed onto or pluggedinto a connection section are described in this disclosure. Theconnection section may be part of a blood treatment apparatus, aconnecting adapter, a fluid line, or the like. The fluid coupling may bepart of a fluid line or fluid communication, for example between theblood treatment apparatus and the fluid line or between the connectingadapter and the fluid line.

The fluid coupling preferably serves a connection of lines, in whichmedical fluids such as blood or dialysate are carried. Therefore, it maybe denoted as a medical fluid coupling.

The fluid coupling may for example serve the connection of a bloodtreatment apparatus to a fluid line. The former may be a blood filter ora dialyzer. The latter may be a blood or dialysate line.

The connection section may be in particular a tube connector.

The fluid coupling comprises at least one first component which isreferred to herein as main body (these two expressions are exchangeableherein), however in certain embodiments it may also be referred to ashandle part or housing part. The main body comprises a receiving sectionfor receiving one end of a fluid conduit or pipe of the connectionsection. The main body further comprises at least one first latchingelement and one optional second latching element.

The first latching element comprises a first section which is designedto be elastically bendable or tiltable. The first section is onlypreferably arranged at a free end of the first latching element or itforms the end of the first latching element at its free end.

The second latching element comprises a section, referred to herein assecond section. The latter is purely preferably arranged at one end ofthe second latching element or it forms the end of the second latchingelement at its free end. The second latching element is purely optionaland it is not indispensable.

At least the first latching element and/or the second latching elementcomprise a recess or a protrusion. The recess, if any, serves thereception of a protrusion of the connection section, which in turn ispart of, e.g., a blood treatment apparatus or of a connecting adapter.The protrusion, if any, serves the engagement or interlocking in arecess of the connection section.

In this, the recess or the protrusion is arranged, when being part ofthe first latching element, such that it faces the second latchingelement (and/or the receiving section), and/or vice versa. Additionallyor alternatively, the recess or the protrusion is arranged at an innerside of the respective latching elements.

The system described herein includes at least one fluid coupling and atleast one connection section, or it comprises both. The fluid couplingand connection section are embodied and provided to latch to each otherin a latching connection and preferably in fluid communication. Thelatter takes place preferably as a non-positive and/or positiveconnection.

Certain aspects of this disclosure further relate to a blood treatmentapparatus or to a connecting adapter with at least one connectionsection respectively. The connection section is embodied and provided tobe latched in a latching connection and preferably in fluidcommunication with at least one fluid coupling. The connection sectionmay thereby be embodied and provided to have protrusions or recesseswhich are suitable, designed and/or provided for establishing a latchingconnection with a fluid coupling while achieving a fluid communicationbetween a fluid conduit of the connection section and the fluid guidingsection of the fluid coupling.

The medical or medical technical blood treatment apparatus describedherein (hereinafter in short: treatment apparatus) is designed to serve,in connection to a blood treatment machine, for the dialysis,hemodialysis, hemodiafiltration, filtration or apheresis. It may be ablood filter, dialyzer or the like.

The tube line for medical use described herein comprises at least onefluid coupling.

The medical or medical technical blood treatment machine describedherein is connected to a blood treatment apparatus in fluidcommunication. The blood treatment machine may serve for the dialysis,hemodialysis, hemodiafiltration, filtration or apheresis and maycomprise devices necessary thereto, like blood pumps etc.

In all of the embodiments, the use of the expression “may be” or “mayhave” and so on, is to be understood synonymously with “preferably is”or “preferably has,” and so on respectively, and is intended toillustrate an embodiment.

Embodiments may comprise one or several of the aforementioned orfollowing features in any combination.

Whenever numerical words are mentioned herein, the person skilled in theart shall recognize or understand them as indications of numerical lowerlimits. Unless it leads the person skilled in the art to an evidentcontradiction, the person skilled in the art shall comprehend thespecification for example of “one” always as “at least one”. Thisunderstanding is also equally encompassed in some embodiments as theinterpretation that a numeric word, for example, “one” may alternativelymean “exactly one”, wherever this is evidently technically possible forthe person skilled in the art. Both are encompassed in certain aspectsand apply herein to all used numerical words.

The spatial indications “top” and “bottom” are to be understood herein,in case of doubt by the person skilled in the art, as absolute orrelative spatial indications which refer to the alignment of therespective component during its common use.

In certain exemplary embodiments described herein, the recess comes toexistence when no external forces are applied on the first and/or thesecond latching element. Thus, by acting on the first and/or secondlatching element and its elastic deformation, the recess may thereforebe removed or its geometry may be changed such that a retaining orholding back of the protrusion is notfluid coupling ensured anymore.Alternatively, acting on the first and/or second latching element andits elastic deformation may change the geometry of the recess such thata retaining or holding the protrusion in all shifting directions is notensured. The recess is to be observed again when the active, elasticdeformation is completed. This can be implemented for example by adesign in which the free end section of the first and/or the secondlatching element is arranged relative to the remaining latching elementor to the main body in a tiltable, foldable or movable manner, orotherwise arranged, in particular against material restoring forces ormaterial resistance.

In certain exemplary embodiments, the main body comprises a fluidguiding section extending through its interior which extends through themain body in its longitudinal direction. The fluid guiding section canbe a fluid canal.

In certain exemplary embodiments, the main body is integrally formed, inothers it is a multi-part.

In certain exemplary embodiments, the protrusion or the protrusions ofthe connection section are designed as a latching edge. The latter maybe circumferential, i.e. surrounding the whole or only sections of thecircumference of the component carrying it, e.g. of the connectionsection.

In certain exemplary embodiments, at least one of the latching elementsis designed as latching wing, clamp wing, arm, component which carriesthe recess or the extension, or the like.

In some exemplary embodiments, the second section of the second latchingelement is also designed as elastically bendable or elasticallytiltable. In such embodiments the latching is carried out by elasticallybending or tilting both latching elements. In others, it is enough toelastically bend or tilt only the first latching element. The secondlatching element, if available, serves as a counter-bearing in case itdoes not comprise any elastic section.

In certain exemplary embodiments, the first section of the firstlatching element and, the second section of the second latching elementor the receiving section, are in a non-connected state, arranged havinga first distance between each other such that, during the process ofconnecting or for the purpose of connecting the fluid coupling to theconnection section, the first distance becomes or has to become a seconddistance, even if this is only temporarily the case. The second distancemay be larger than the first distance.

In certain exemplary embodiments, the first and second distance aresituated in the same plane.

In some particular embodiments, the first section of the first latchingelement and the second section of the second latching element are in oneplane or are movable within a common plane for connecting or releasingthe connection. This advantageously allows to easily release theconnection using only one hand.

In certain exemplary embodiments, the first section of the firstlatching element and/or the second section of the second latchingelement is a tiltable section or is arranged in a tiltable manner at afurther section of the respective latching element.

In certain exemplary embodiments, the first and/or the second latchingelement are produced as integral or a one-piece sections of the mainbody.

In certain exemplary embodiments, an inner diameter of the fluid guidingsection of the main body, which particularly extends in longitudinaldirection of the main body, remains constant and is between 4.0 and 4.5mm, and more preferably 4.2 mm.

In certain exemplary embodiments, the main body is made of or comprisesa first material. In addition, the fluid coupling comprises a sealingelement made of a second material which is different from the firstmaterial.

In certain exemplary embodiments, the sealing element comprises athrough opening with exactly or at least one inner diameter, whichcorresponds or is identical to an inner diameter of the fluid guidingsection of the main body.

In certain exemplary embodiments, the main body comprises, in additionto the first end area and to the second end area of the fluid guidingsection, at least one further opening. The opening is closable by meansof a septum and comprises such a septum optionally. This opening issituated in or opens out into, preferably between the first end area andthe second end area, the fluid guiding section.

In certain exemplary embodiments, the main body comprises the fluidguiding section as a main canal with a lumen for guiding a first fluidthrough the fluid coupling. The main body comprises further a secondarycanal outlet of a secondary canal for adding a second fluid into themain canal. In this, the fluid coupling comprises at least one actuatingelement which is arranged relative to the main body to be transferrable,positionally adjustable, or movable between a first position and asecond position. Furthermore, the fluid coupling comprises a sealingsection which is arranged, to be twistable when the actuating element isbeing transferred from one position into the other, between a firstposition of the sealing section, in which the sealing section does notclose or cover the secondary canal outlet (open position), and a secondposition of the sealing section, in which the sealing section closes orcovers the secondary canal outlet (closed position).

In certain exemplary embodiments of the system, the inner diameter ofthe fluid guiding section and an inner diameter of a fluid conduit ofthe connection section are substantially or completely the same in anarea of a front face assigned to or facing the fluid guiding section.

In certain exemplary embodiments of the system, the inner diameter ofthe fluid guiding section, an inner diameter of a sealing element and aninner diameter of the fluid conduit are substantially or completely thesame in an area of a front face assigned to or facing the fluid guidingsection.

In certain exemplary embodiments, the tube line is maximally 200 mm(millimeter), or 150 mm maximally, or maximally 100 mm long.

In some exemplary embodiments, the fluid coupling is not a screwconnector, the fluid coupling comprises no thread and/or no thread isprovided, for its connection, with any threaded nut or cap nut, nor isit connectable thereto.

In some particular embodiments, the fluid coupling is part of the fluidline, i.e. that a section of the fluid coupling, herein denoted as fluidguiding section, is perfused or may be perfused by fluid when used asintended, as this section is part of a flow path or conduit.

The tube which is connected to the fluid coupling in some embodimentsmay itself be connected to a blood cassette. The blood cassette may be ahard part, which is closed, at least at one side, against theenvironment by a film and/or is connected to the film.

In certain embodiments, the first latching element and/or the secondlatching element are designed as a bending fork. The first latchingelement and/or the second latching element may comprise one or severaldetent lugs which may be provided at the bending fork.

In exemplary embodiments, the recesses of at least one latching elementare designed at an inner side or a lower side thereof.

In some embodiments, the fluid coupling is designed to be connected tothe connection section exclusively by latching the first latchingelement and/or the second latching element, and by inserting the fluidconduit or a face section thereof in the receiving section as well asoptionally by sliding on of an external conduit or pipe of theconnection section onto the receiving section.

In some exemplary embodiments, the main canal is a pipe.

In some exemplary embodiments, the sealing section is arranged ordesigned not to impair an access to the main canal for the first fluidneither in its first position nor in its second position.

In some exemplary embodiments, there is no section of the sealingsection in the lumen of the main canal.

In some exemplary embodiments, the main canal comprises in addition tothe secondary canal outlet a septum outlet which, during use of thefluid coupling, is closed by a septum penetrable by a cannula.

In some exemplary embodiments, the secondary canal outlet and/or theseptum outlet extend or open up into a straight extending section of across section of the lumen or its circumference of the main canal.

In some exemplary embodiments, the sealing section comprises afront-face sealing surface which is arranged to be moved during therotation of the sealing section along a rotation curve from a firstposition into a second position on the rotation curve, wherein thesealing surface closes or covers, in the second position, the secondarycanal outlet, wherein the sealing surface does not close or cover, inthe first position, the secondary outlet, and wherein the sealingsurface extends parallel to a main cross section plane and/or verticallyto a rotation axis of the sealing section.

In some exemplary embodiments, the sealing section comprises a sealinglug, which protrudes from it in an axial direction of the sealingsection, wherein the sealing lug is arranged to be moved on a rotationcurve from a first position into a second position on a rotation curve,at a rotation of the actuating element or at the transferring of theactuating element from one position into another, wherein the sealinglug does not close or cover the secondary canal outlet in the firstposition, and wherein the sealing lug closes or covers the secondarycanal outlet in the second position.

In some exemplary embodiments the housing element comprises at least onesection which comprises a recess for receiving the sealing lug movableherein, and which comprises or abuts or is adjacent to the secondarycanal outlet.

In some exemplary embodiments, the sealing lug comprises a groove whichis open towards both a front face of the sealing lug and to a lateralside surface or peripheral surface of the sealing section.

In some exemplary embodiments, the groove is disposed, in the firstposition of the sealing section, against an opening of a secondary canalpipe such that it continues the fluid path of the secondary canal pipeacross the sealing section, wherein the groove is not, in the secondposition of sealing section, in fluid communication with the secondarycanal pipe or its opening.

In some exemplary embodiments, the sealing section comprises in additionto its front-face sealing surface or in addition to its sealing lug, aprojecting, closed sealing structure which, in the second position ofthe sealing section, closes the opening of the secondary canal pipe orprevents an exit or escape of fluid out of the opening.

In some exemplary embodiments, the sealing section is a separate sealingelement.

In some exemplary embodiments, the sealing section comprises at leastone pierceable septum.

In some exemplary embodiments, both the septum outlet and the secondarycanal opening are arranged together in one half of a cross section ofthe main canal.

In some exemplary embodiments, the fluid coupling comprises a receivingsection for receiving or fixing, in particular temporarily, a protectioncap, in particular provided for covering a secondary canal pipe or asecondary canal connector, onto the fluid coupling.

The fluid coupling comprises preferably a fluid guiding section throughwhich fluid may flow through the fluid coupling in a longitudinaldirection thereof. The fluid guiding section defines therewith thelongitudinal direction or longitudinal axis of the fluid coupling.

The fluid guiding section comprises a first end area and, opposite tothe latter, a second end area. Both the first end area and the secondend area may connect the fluid guiding section to the exterior of themain body.

The fluid guiding section may optionally have the smallest diameter ofall structures of the main body perfused during use by fluid in thelongitudinal direction of the main body.

In some exemplary embodiments, the perfused diameter or inner diameterof the fluid guiding section is smaller than the inner diameter of thefirst connection section.

In some exemplary embodiments, the perfused diameter or inner diameterof the fluid guiding section may be smaller than the inner diameter ofthe tubular expansion of the second connection section.

Both the first latching element and the second latching element may havea width—e.g. indicated as length or circumference degree, which is eachonly a fraction of the circumference of the fluid coupling.

For establishing a fluid communication between the fluid guiding sectionand the fluid conduit of the connection section, the fluid couplingcomprises in some embodiments a free space between the outercircumference of the tubular expansion of the second connecting sectionand the latching elements. This free space is optional and provided toreceive an outer conduit or pipe of the connection section herein.

The tubular expansion may be designed to receive within its interiorboth the sealing element and at least also sections of the fluid conduitof the connection section.

The sealing element comprises in some particular embodiments an openingwhich optionally comprises at least two opening cross sections or innerdiameters different from each other. The sealing element may optionallycomprise in addition at least two outer diameters different from eachother.

In addition, the sealing element may comprise a peripheral bead at itsend which is, during use, adjacent to the second end area. Theperipheral bead may, when it is inserted in an optional peripheralgroove at the inner circumference of the second connecting section,account for a further improvement of the sealing effect.

The fluid coupling may be exactly two-part, and may comprise, inaddition to the main body itself, a sealing element.

The tubular expansion has in some exemplary embodiments more than onlyone diameter, each of which is larger than the inner diameter of thesecond end area or of the fluid guiding section.

Some or all of the embodiments may encompass one or several of theaforementioned or following advantages.

The fluid coupling described herein may offer advantages in that thefluid coupling comprises or requires no threads and/or no union nutwhich in turn advantageously allows a manual arrangement of the fluidcoupling relative to a blood treatment apparatus which comprises theconnection section. In contrast to, for example the tightening of theunion nut, the fluid coupling remains in the desired rotation position.The unwanted rotation of the connector observed in the case of unionnuts due to a competing friction situation, in the last almost 30degrees of tightening, between the union nut and the connector and theconnector and the blood treatment apparatus does not occur. Thereby, thedesired or intended position or rotating orientation with which thefluid coupling is plugged onto the connection section, is advantageouslymaintained. Further functions may therefore be well or suitablyintegrated, for example a pierceable septum in the connector. Thepierceable septum often necessitates an exact rotational orientationwith respect to the dialyzer and with respect to the blood treatmentdevice. This is beneficial as it may lessen the space taken up byapparatuses, tubes, and equipment during treatment.

Furthermore, the fluid coupling spares the user a troublesome ordifficult unscrewing during which, undesirably high and potentiallydamaging torques may be applied.

A passive contact protection of the relevant areas of the connecting orconnection outlet is advantageously achieved. Therefore no protectioncap is required and contamination through a failure in the commonhandling is advantageously prevented.

Advantageously, the fluid coupling does not need to have a materialwhich comprises a plasticizer. Materials containing plasticizer areknown in connectors of the prior art; they serve a better sealing whenscrewing on the connector with an ergonomically acceptable torque. Theyare not required due to a lack of a screw connection.

The fluid coupling may advantageously be used for connecting arbitrarilyshort tubes, as no twisting which may lead to tube buckling.

The fluid coupling is optimized with respect to its handling. It isadvantageously easily connected and released, which may take place usingone hand and without requiring a large space for the hand or hands. Thisis different compared to the operation of thread connectors known in theart.

The fluid coupling is connected only by means of plugging or latching.The completion of the connecting process is clearly transmitted to theuser, for example through the audible and/or tactile click at the fluidcoupling, namely when the latching elements glide over the protrusionsof the connection section and the protrusions latch into the recesses orlatching elements (or protrusions of the latching elements into therecesses of the connection section). Hereby, the user receives reliablefeedback regarding whether the desired connection has been achieved ornot.

If a malfunction occurs, the fluid coupling may be manually removed byfluid coupling manually spreading apart the latching element (which maycomprise e.g. snap tongues or tiltable sections as elastic, first andsecond sections) or by pressing the latching elements together,depending on the embodiment. A removal by the user is however notpossible. The latching is furthermore optically directly verifiable.

The fluid coupling comprises, in its interior, no dead zones of theflow, dead spaces or sharp edges. This contributes to a goodventilation, rinsing or flushing, and hemo-compatibility. The same alsoapplies to the junction between the fluid guiding section and fluidconduit of the connection section.

In exemplary embodiments, the diameter of the fluid guiding section,which may also be denoted as canal diameter, is constant; in someembodiments, it is comparatively small (e.g. between 3.5 and 5.0 mm,preferably 4.0 to 4.5 mm, particularly preferred is 4.2 mm, preferablysmaller than 6.0 mm). Both reduce the probability of the remaining fluidexiting when disconnecting the fluid coupling.

In exemplary embodiments, the sealing element, e.g. the sealing ring, ismade of silicon rubber. Such material selection contributes to the factthat the fluid coupling is well automatically mountable and easilysteam-sterilizable. This material selection contributes also to atolerance-insensitive radial sealing due to the very distinct axialflexibility of the sealing element and to a bridging of dimensionaltolerance with no dead spaces.

The presence or use of silicon rubber in the material in this, is onlyabout one third of that required, for example, in known check valves.The fluid coupling is distinguished through an inexpensive productionprice.

In exemplary embodiments, the second end area of the fluid guidingsection, which is connected during use in fluid communication to eitherthe sealing element or, when no sealing element is provided, to a frontface of the fluid conduit of the connection section, is shifted back asagainst the tubular expansion. The latter ensures a permanent contactprotection of the surfaces of the fluid coupling relevant during theconnection. A protection cap for the fluid guiding section mayadvantageously be dispended with. Such a solution also offers protectionagainst cough drips.

In exemplary embodiments, the main body and, if any, the septum hood ismade of PP (Polypropylen).

The septum may be made of known septum rubber.

In some particular exemplary embodiments, the septum is advantageouslyflush without an inner diameter step with the fluid guiding section,which is exemplarily designed as a blood canal.

In some exemplary embodiments, the access to the septum by the useradvantageously remains in a constant rotating position with respect tothe connection section. Advantageously, the septum access does notjointly rotate when using the fluid coupling.

In some exemplary embodiments, the cover is connected through afilm-snap-joint to the main body of the fluid coupling. This allows adistinct protection against coughing over the septum. In addition, theperiod of safe sterility is extended or prolonged. However, also alreadydue to the shifted-back position of the septum with regard to thesurface of the main body, the septum may advantageously be considered tobe permanently contact-protected and yet may be easily sprayed withdisinfectant.

In some exemplary embodiments, the septum hood is produced in a simpleand cost-effective manner by means of on-off tools. It allows,nevertheless, a non-releasable and a mechanically precise or accuratelatching with the fluid coupling.

In some embodiments, the septum hood comprises at least one element bymeans of which a pressing of the septum is carried out, preferablycontinuously. Such pressing protects the septum from accidently being orbecoming released or leaky, particularly due to a prevailing fluidpressure in the fluid guiding section adjacent to the septum.

Some exemplary embodiments are advantageously compatible with steamsterilizing methods, which are advantageous as breakthroughs orapertures and/or drainage structures of some embodiments may bedifficult to sterilize using other methods.

In some embodiments, the fluid coupling is connectable through pluggingand latching, without necessitating a rotating movement, for example athread connection. Accordingly, an insertion in an improper orientationwith a subsequently required rotation of the tube may advantageously beprevented. In addition, there is no twisting accompanied by or withgeneration of a restoring force. With that, an unwanted release of theconnection may be prevented. Thereby, very short tubes (100 mm long orshorter) may be used, for their connection when no rotating movement isrequired. There is no twisting (kinking) even in connecting very shorttubes. Short tubes are cost effective as less tube material is used.Furthermore, less blood is extracorporally conducted than in the known,long tubes. Additionally, long tubes are hard to handle as they may forexample get jammed when closing doors, lids etc. of the treatmentapparatus, for instance when pressing the blood cassette behind a doorof the treatment apparatus. These two last-mentioned disadvantages maybe reduced or cancelled in some embodiments.

In some exemplary embodiment, additional tube connections for lueraddition tubes or with direct luer-connecting pieces or nozzles areoptionally simply integrated or integratable in the main body of thefluid coupling for luer addition tubes or with direct luer-connectingpieces or nozzles.

In some exemplary embodiments, the latching elements are arrangedsymmetrically, preferably in mirror symmetry. Such symmetryadvantageously allows to actuate the latching elements easily andwithout tension, for release of the connection using one hand.

The fluid coupling and the integrated septum are beneficial, incomparison with the known chain-arrangement of a known septum-tubeaddition site and with a known screw connector in a connecting tube.

An advantage of certain aspects may be to propose a further connectorfor providing a fluid communication between two systems which carry amedical fluid. Furthermore, suitable devices, which are directly orindirectly connected to the connector, are to be specified.

Some embodiments shall be exemplarily explained with regard to theaccompanying drawings in which identical reference numerals refer to thesame or similar elements. The following applies in the partly highlysimplified figures:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a perspective view of a main body of a fluid coupling in afirst embodiment;

FIG. 2 shows a side view of a sealing element for use with the main bodyof FIG. 1;

FIG. 3 shows a slightly perspective, longitudinal section view of thefluid coupling of the first embodiment with the main body of FIG. 1 andthe sealing element of FIG. 2, wherein the fluid coupling is connectedto a connection section;

FIG. 4 shows a perspective view of a main body of a fluid coupling in asecond embodiment with an additional opening as a further fluidconnection to a fluid guiding section of the main body;

FIG. 5 shows a perspective view of a sealing element for use with themain body of FIG. 4;

FIG. 6 shows a perspective view of a septum hood for use with the mainbody of FIG. 4;

FIG. 7 shows a longitudinal section view of the fluid coupling of thesecond embodiment with the main body of FIG. 4, the sealing element ofFIG. 5, and the septum hood of FIG. 6, wherein the fluid coupling isconnected to a connection section;

FIG. 8 shows the fluid coupling of FIG. 7 with septum hood, but with nocover, perspectively;

FIG. 9 shows the fluid coupling of FIG. 8 with closed cover of theseptum hood, which is similar to that of FIG. 6;

FIG. 10 shows the fluid coupling of FIG. 9 with septum hood having anopened cover;

FIG. 11 shows a perspective view of the fluid coupling in a thirdembodiment connected to a blood treatment apparatus;

FIG. 12a, b show a top view, and two different positions, of the mainbody of a fluid coupling in a fourth embodiment as part of a system;

FIG. 13a, b show a top view of, and two different positions, the mainbody of a fluid coupling in a fifth embodiment as part of a system;

FIG. 14 shows the sealing element of FIG. 2 and its arrangement in themain body according to FIG. 3; and

FIG. 15 shows a sealing element, alternative to that of FIG. 2, and itsarrangement in a main body of the fluid coupling, alternative to that ofFIG. 3.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1 shows a perspective view of the main body of an exemplary fluidcoupling 100 in a first embodiment. Fluid coupling 100 is hereinafterdescribed also with reference to FIG. 2 and FIG. 3.

The fluid coupling 100 comprises or defines a fluid guiding section 1,through which fluid may flow through the fluid coupling 100 in alongitudinal direction thereof. The fluid guiding section 1, thus,defines or determines the longitudinal direction or longitudinal axis ofthe fluid coupling 100.

The fluid guiding section 1 comprises one first end area 2 and, oppositeto it, one second end area 3. Both the first end area 2 and the secondend area 3 can connect the fluid guiding section 1 to the exterior ofthe main body, as shown in FIG. 1.

The fluid guiding section 1 may be designed as a canal, channel,conduit, or lumen. It may optionally comprise the smallest diameter ofall structures of the main body through which fluid flows during use inthe longitudinal direction of the main body.

The fluid coupling 100 comprises a first connecting section 4 in thearea of the first end area 2 and a second connecting section 5 in thearea of the second end area 3. The second connecting section 5 isexemplarily designed as tubular expansion which is here denoted likewisewith the reference numeral 5.

The first connecting section 4 serves as a fluidic connection of thefluid coupling 100, of its first end area 2 or of the fluid guidingsection 1 with a fluid system, e.g. to the end of a tube line.

The second connecting section 5 serves as a fluidic connection of thefluid coupling 100, of its second end area 3 or of the fluid guidingsection 1 with a fluid conduit 301 of the connection section 300 shownfirst in FIG. 3. The fluidic connection between the second end area 3and the connection section 300 is, in the exemplary embodiment of FIG.1, indirect, as the second end area 3 is in direct contact to a sealingelement 200, but not connected directly to the connection section 300itself. The sealing element 200 is itself in direct contact to theconnection section 300 and is in fluid communication therewith.

The second connecting section 5 serves as receiving section for one endof the fluid conduit 301.

In the exemplary embodiment of FIG. 1, the second connecting section 5,which is herein exemplarily designed as tubular expansion 5, is lined upto the second end area 3 with a larger distance to the first end area 2than to the second end area 3.

The perfused diameter or inner diameter of the fluid guiding section 1is, in exemplary embodiments such as the one shown in FIG. 1, smallerthan the inner diameter of the first connecting section 4. Thus, one endof a tube 30, first shown in FIG. 11, of the non-shown fluid system maybe inserted into the first connecting section 4 by gluing or clampingand hence may be inserted into the main body. Due to such design, it maybe connected to the main body such that no jump in diameter is caused atthe junction of the tube end and the fluid guiding section 1, therebypreventing turbulences due to rapidly changing flow cross sections anddead spaces.

The perfused diameter or inner diameter of the fluid guiding section 1is, in exemplary embodiments such as the one shown in FIG. 1,additionally or alternatively to what is stated in the previousparagraph smaller than the inner diameter of the tubular expansion ofthe second connecting section 5. If, as seen in the exemplary embodimentof FIG. 1, the inner diameter of the tubular expansion is larger thanthat of the fluid guiding section 1, then the sealing element 200 may beinserted into the tubular expansion and thus into the main body and maybe connected therewith through clamping or latching, without causing ajump in diameter at the junction of the sealing element 200 and thefluid guiding section 1. The latter advantageously prevents turbulencesdue to rapidly changing flow cross sections and prevents dead spaces.Furthermore, this design brings the sealing element 200 in contact withthe connection section 300, without changing the perfused diameter inthe area of the sealing element 200, thereby increasing the sealingeffect.

The fluid coupling 100 comprises a first latching element 15 and apurely optionally provided second latching element 17. In the exemplaryembodiment of FIG. 1, both protrude in longitudinal direction of themain body over a free end of the second connecting section 5.

The first latching element 15 is elastically designed in a first section15 b thereof, i.e. the end of the latching element 15 shown in FIG. 1 onthe right. Optionally, also the second latching element 17 iselastically designed in a second section 17 b thereof, the end of thelatching element 17 shown in FIG. 1 on the right. Due to theirelasticity, the first and second section 15 b, 17 b may to a certainextent be moved apart from each other under application of force, tomove again towards each other after removal of the force. Optionally,the first section 15 b and the second section 17 b are the sections ofthe first or second latching element 15, 17 by means of which the latterprotrude over the free end of the second connecting section 5.

Both the first latching element 15 and the second latching element 17have a width which—e.g. indicated as length or circumference degree—eachmake up only a fraction of the circumference of the fluid coupling 100in a third area 19, in which both the first latching element 15 and theoptional second latching element 17 are connected to the remaining fluidcoupling sections. In other words, both latching elements 15, 17 areoffset from each other, there is a space between them in the peripheraldirection of the fluid coupling 100.

Both the first latching element 15 and the second latching element 17have, in the exemplary embodiment of FIG. 1, a recess 15 a of 17 a,respectively. Both recesses 15 a, 17 a are provided to receive one orseveral protrusions 305 a of the connection section 300, one of which isfirst shown in FIG. 3. The connection section 300 is releasably coupledto the fluid coupling 100, and vice versa, by receiving the protrusions305 a in the recesses 15 a and 17 a—and, where appropriate, by leading afluid conduit 301 of the connection section 300 in the interior of thesecond connecting section 5 as a reception section, herein exemplarilydesigned as tubular expansion 5, as well as by pushing an outer pipe 310(shown first in FIG. 3) over the tubular expansion.

The connection between the protrusions 305 a and the recesses 15 a and17 a is non-destructively detachable. The fluid coupling 100 istherefore reusable.

To connect the fluid coupling 100 to the connection section 300 as shownin FIG. 3, the fluid coupling 100 is pushed onto the connection section300. Thereby, the distance between the first latching element 15 and thesecond latching element 17 increases due to the expanding effect of theprotrusions 305 a, further increasing until the recesses 15 a and 17 aslide over the protrusions 305 a and receive them due to the elasticity.When this is accomplished, the procedure of connecting, whichrecognizably is or encompasses latching, is terminated. The desiredconnection is achieved.

In order to release the connection, the first latching element 15 and,if provided, the second latching element 17 are spread apart manually,i.e. deformed against their elastic resistance, such that the distancebetween the first section 15 b and the second section 17 b is enlargedto the point that their recess 15 a or 17 a, respectively, sufficientlyreleases the protrusions 305 a, so that it is possible to release theconnection section 300 by pulling the fluid coupling 100 or vice versa.

The fluid guiding section 1 may be enveloped by, or may comprise, at itscircumference a web-honeycomb structure 11. Due to its inhomogeneoussurface texture, one can securely take hold of the fluid coupling 100 byhand. At the same time, it supports the fluid guiding section 1 andprotects it from mechanical damage, e.g. by kinking.

The fluid coupling 100 comprises free spaces 15 c, 17 c, as seen in FIG.1, between the outer circumference of the tubular expansion of thesecond connecting section 5 and the latching elements 15, 17,respectively, for establishing a fluid communication between the fluidguiding section 1 and the fluid conduit 301 of the connection section300. Such free spaces 15 c, 17 c are optional and provided to receivethe sections of the outer conduit or pipe 310 of the connection section3. The outer pipe 310 encloses the fluid conduit 301 of the connectionsection 300 located in its interior, for example concentrically.

In some embodiments, the fluid coupling 100 consists of the main body,as it is shown in FIG. 1 or in other embodiments. In other embodiments,the fluid coupling 100 comprises in addition to the main body at leastone sealing element 200, as shown in an exemplary embodiment in FIG. 2.The latter exemplary embodiments include the embodiment shown in FIG. 1,in which the sealing element 200 is provided (exemplarily designed asshown in FIG. 2).

The tubular expansion 5 is embodied such that it receives both thesealing element 200 and at least also sections of the fluid conduit 301of the connection section 300 in its interior as shown in FIG. 3.

FIG. 2 shows a sealing element 200 optionally designed as a sealing ringand provided to be inserted in the tubular expansion of the secondconnecting section 5 of the main body of the fluid coupling 100.

The sealing element 200 comprises an opening therethrough having,optionally, at least two different opening cross sections or innerdiameters. The sealing element 200 may, optionally, additionallycomprise at least two different outer diameters. Both are seen in FIG.2.

Additionally, the sealing element 200 may comprise at its end, abuttingduring use the second end area 3, a peripheral bead 210. The peripheralbead 210 may, when it is inserted or guided into an optional peripheralgroove 25 at the inner circumference of the second connecting section 5,account for additional improvement of the sealing effect.

FIG. 3 shows the fluid coupling 100 of FIG. 1 with the sealing element200 of FIG. 2, wherein the fluid coupling 100 is connected in fluidcommunication with the previously aforementioned connection section 300.Hence, FIG. 3 shows the system in an exemplary embodiment.

It is seen in FIG. 3 how the recess 15 a of the first latching element15 receives the protrusion 305 a of the connection section 300. Thelatching element 15 is illustrated with respect to its inner side, whichmay be its bottom or lower side.

As seen in FIG. 3, which shows exactly only one latching element, it maybe sufficient in some embodiments to ensure the connection between thefluid coupling 100 and the connection section 300 by only exactly onelatching element by means of latching, wherein this connection isgenerated by inserting the fluid conduit 301 into the second connectingsection 5 and by snapping or plugging the outer pipe 310 on the outercircumference of the second connecting section 5.

The sealing element 200 comprises a first inner diameter (which is seenat the left end of the sealing element 200 in FIG. 3) which correspondsto the inner diameter of the second end area 3 or the fluid guidingsection 1 of the fluid coupling 100. Such correspondence or matching isnot necessarily required, however it offers the advantage of afluidically advantageous passage between the second end area 3 and thesealing element 200 such that turbulences of fluid flowing betweensealing element 200 and second end area 3 are prevented or decreased.

The fluid coupling 100 may be regarded as a two-piece fluid coupling100, which, if desired, may consist of exclusively its main body withthe first and optionally the second latching element 15, 17, as depictedin FIG. 1, as well as of the sealing element 200 of FIG. 2.

As seen in FIG. 3, but also already in FIG. 1, the tubular expansion ofthe second connecting section 5 may join or connect to the second endarea 3 of the main body. It may, as depicted in FIG. 3, serve forreceiving the sealing element 200 in its interior and hereunto be stillradially wider as compared to the inner diameter of the second end area3, i.e. having a larger diameter. The larger diameter allows the sealingelement 200 to be arranged in the tubular expansion and concurrently incontact to the second end area 3, such that a passage from the secondend area 3 to the sealing element 200 may be provided without a step orchange of diameter.

In the depicted embodiment, the tubular expansion 5 has more than onediameter, each of which is larger than the inner diameter of the secondend area 3 or of the fluid guiding section 1. In the example of FIG. 1and FIG. 3, there are specifically at least two such diameters at whichthe sealing element 200 contacts each one peripheral section of thetubular expansion 5 respectively.

It is seen that the sealing element 200 is designed to contact both thefront side of the mouth section of the fluid conduit 301 and acircumferential side (along the closed circumference) of the fluidconduit 301 at the fluid conduit 301. In this manner, a double sealingis established, one time at the front side, another time at thecircumference, of the fluid conduit 301 respectively, i.e. both axiallyand radially. Such double sealing is possible by a stepped constructionor design of the sealing element 200 which is established or achieved byproviding more than only one inner diameter of the sealing element 200.

It should be noted that the special design of the main body and/or ofthe tubular expansion 5 of the main body is adapted to the specialdesign of the sealing element 200, as described herein. However, shoulda sealing element be provided, which does not prevent but allows, duringuse, a contact between second end area 3 and front side of the fluidconduit 301 of the connection section 300 (e.g., as shown in FIG. 15),then it is likewise encompassed in some embodiments.

FIG. 4 shows a perspective view of a main body of an exemplary fluidcoupling 100 in a second embodiment.

The fluid coupling 100 of this embodiment comprises the main body shownin FIG. 4, which differs from the main body of the fluid coupling 100 ofFIG. 1 by having an addition or withdrawal opening 21. The opening 21represents a portal facilitating fluid communication between an exteriorof the fluid coupling 100 and the interior of the fluid guiding section1 of the main body. The opening 21 is configured to allow the additionof fluid to the fluid flowing through the fluid coupling 100 in thefluid guiding section 1 between first end area 2 and second end area 3.The fluid added via the opening 21 may be medicament.

The opening 21 to the fluid guiding section 1 may be designed to beaccessible from one side of the main body, e.g. a side of a gripsection. The opening 21 serves for the adding, for example, ofmedicament to the fluid flowing through the fluid coupling 100 in thefluid guiding section 1 between first end area 2 and second end area 3.

The opening 21 is recognizably disposed in a recess of the main body.The opening 21 is closed, during use, by means of a septum 23, initiallyseen in FIG. 7 and exemplarily made of rubber. The recess establishes aspace between the opening 21 or an outer surface of the rubber of theseptum 23 on the one side, and an outer of the surface of the main body,e.g. the bar-honeycomb structure 11 on the other side. Such spaceensures that the septum 23 cannot be touched by an operator because theopening 21 is too small for the finger to reach into it. The septum 23is however at the same time accessible enough to be reached via acannula or spray disinfection.

FIG. 5 shows a sealing element 202 for the fluid coupling 100 of FIG. 4.It may optionally be used as the septum 23.

FIG. 6 shows a septum hood 400 which may optionally be used togetherwith the fluid coupling 100 of FIG. 4. The septum hood 400 may comprisea cover 401 whose back side is seen in FIG. 6 in the center of theseptum hood 400. The cover 401 is closed in FIG. 9.

The septum hood 400 is designed to cover the recess, which is disposedin front of the opening 21 or the septum 23 with regard to the view ofthe user, against the main body of the fluid coupling 100.

The septum 23 may be repositioned by about 1 to 15 mm, preferably byabout 2 to 10 mm, more preferably by about 3 to 5 mm.

The septum hood 400 may be designed with respect to the surface of themain body with which the septum hood 400 is flush to form a non-steppedclosure of the recess.

The septum hood 400 may comprise hooks, detent lugs 403 or protrusionsfor fastening it to the main body. The main body may comprisecorresponding recesses or undercuts for receiving or latching the septumhood 400. Other fastening modes are likewise envisioned within the scopeof this disclosure.

FIG. 7 shows, in a longitudinal section, the fluid coupling 100 of FIG.4 with a sealing element 200 of FIG. 2. Both are connected to theconnection section 300 as intended. FIG. 7 shows thereby the system in afurther exemplary embodiment.

The double, i.e. both radial and axial, fluidic sealing of the fluidguiding section 1 against the fluid conduit 301 of the connectionsection 300 by the sealing element 200 is also seen in the secondembodiment of FIG. 7. Nevertheless, this feature is optional in eachembodiment.

FIG. 8 shows the fluid coupling 100 of FIG. 4 with septum hood 400,however without cover 401.

FIG. 9 shows the fluid coupling 100 of FIG. 8 with closed cover 401 ofthe septum hood 400, which is again similar to that of FIG. 6.

FIG. 10 shows the fluid coupling 100 of FIG. 9 with septum hood 400having an opened cover 401. A detent lug 403 and a sealing frame 405 areprojecting from the cover 401, which has a circumferential edge thatserves to fix the cover 401 geometrically to the septum hood 400.Furthermore, it may assist to seal the recess against fluid entry.

FIG. 11 shows a perspective view of the fluid coupling 100 in a thirdexemplary embodiment.

The fluid coupling 100 embodiment shown here includes an actuatingelement 40, for actuating or operating a multiway valve provided in thefluid coupling 100, as a further feature to the features which the fluidcoupling 100 of the aforementioned first or second embodiment alreadycomprise. The multiway valve serves for operating at least one secondarychannel, which is contained in a secondary channel pipe 41. An optionalprotection cap has the reference numeral 43.

Further, the fluid coupling 100 is connected to the tube 30 or to theend of a tube line by the first connecting area 4. The connectionsection 300 is similarly in fluid communication with a blood treatmentapparatus 500. Instead of being connected to the blood treatmentapparatus 500 shown in FIG. 11, the connection section 300 may be influid communication with an adapter or may be part thereof.

FIG. 11 shows the fluid coupling 100 with a valve element, which isdescribed in DE 10 2011 108 787 A1 as a port, operable by an actuatingelement 40. The relevant disclosure of which is hereby fullyincorporated by reference.

FIG. 12a, 12b show a top view of the main body of a fluid coupling 100in a fourth embodiment and in two positions, one of which is shown inFIG. 12a and the other in FIG. 12 b.

The connection process in the position shown in FIG. 12a , by which thefluid coupling 100 is shifted from left to right onto the connectionsection 300, is not yet complete, unlike in FIG. 12b . The positionshown in FIG. 12a thus shows the fluid coupling 100 of this exemplaryembodiment before the end of the connection process, which correspondsat the same time however also to the beginning of the release process,i.e. the process by which the fluid coupling 100 is released from theconnection section 300.

The main body shown in FIG. 12a, b differs, with respect to its latchingelement 15, 17, from the main body of each of the aforementionedembodiments in that in the latter, the first elastic section 15 b andthe second elastic section 17 b are each designed as, or comprise, atiltable section having a front end and a back end, respectively. Thefront end is thereby closer to the first connecting section 4 than theback end. The latter may, as exemplarily shown in FIG. 12a, b , closethe main body at or towards a side thereof. The tiltable section 15 b,17 b is arranged, relative to the remaining latching element 15, 17 ormain body respectively, to be tiltable or foldable against materialrestoring forces or material resistance.

By comparing FIG. 12a with FIG. 12b , it is recognizable that the mainbody shown herein in the fourth embodiment differs from those of theaforementioned figures in that the recesses 15 a, 17 a of the latchingelement 15, 17 come to exist only when no external forces are applied onthe tiltable section 15 b, 17 b as first or second section. Suchexternal forces include existing forces with which the user moves theback ends of both tiltable sections 15 b, 17 b towards each other, andforces with which the protrusions 305 a push apart the front ends ofboth tiltable sections 15 b, 17 b.

FIG. 13a , FIG. 13b show a top view of the main body of a fluid coupling100 in a fifth embodiment and in two different positions, one of whichis shown in FIG. 13a and the other in FIG. 13 b.

In the position shown in FIG. 13a , the connection process, by which thefluid coupling 100 is shifted from left to right onto the connectionsection 300, is not yet completed, unlike in FIG. 13b . The positionshown in FIG. 13a thus shows the fluid coupling 100 of this exemplaryembodiment before the end of the connection process, which is at thesame time however also corresponds to the beginning of the releaseprocess, i.e. the process by which the fluid coupling 100 is to bereleased from the connection section 300.

The main body shown in FIG. 13a, b differs with respect to its latchingelement 15, 17 from the main body of FIG. 12a, b in that, the tiltablesections 15 b, 17 b may be opened when the user applies force onto thefront end, such that the protrusion 305 a is released, wherein theprotrusion 305 a pushes apart the back ends during the connectionprocess.

In the designs of FIG. 12a, b and of FIG. 13a, b , unlike in theembodiments of FIGS. 1 to 10, there is thus no pressure applied to oneand the same section of the latching element 15, 17 when connecting aswell as when releasing of connection between recess 15 a, 17 andprotrusion 305 a. In fact, by providing a tiltable section 15 b, 17 b,force is applied on a first end for connecting, and for or release ofthe connection, force is applied on the opposite end of the tiltablesection 15 b, 17 b. That advantageously allows offering a main body inwhich, depending on preferences of the user and with regard to theergonomic and relevant mounting conditions, a spreading-apart, a movingapart, or a pressing together, a moving together may be required forreleasing the connection.

The first and the second section 15 b, 17 b of the latching elements 15,17 are designed as tiltable sections in the embodiments of FIG. 12a, band of FIG. 13 a, b.

FIG. 14 shows the sealing element 200 of FIG. 2 and its arrangement inthe main body according to FIG. 3, in which it prevents a direct contactbetween the end area 3 and the outlet of the fluid conduit 301.

FIG. 15 shows an alternative sealing element 200 and its arrangement inan alternative main body of the fluid coupling 100, in which it does notprevent a direct contact between the end area 3 and the outlet of thefluid conduit 301. It is rather arranged to abut an outer circumferenceof the fluid conduit 301 and an inner circumference of the tubularexpansion 5, but not to abut a surface of the fluid conduit 301.

LIST OF REFERENCE NUMERALS

-   100 fluid coupling-   1 fluid guiding section-   2 first end area-   3 second end area-   4 first connecting section-   5 second connecting section; tubular expansion-   11 web-honeycombs structure-   15 first latching or fixing element-   15 a recess-   15 b first section, tiltable section-   15 c free space or vacuity-   17 second latching element-   17 a recess-   17 b second section, tiltable section-   17 c free space-   19 third area-   21 addition or withdrawal opening, shortly: opening-   23 septum-   25 peripheral groove-   30 tube or tube line-   40 actuating element-   41 secondary canal or branching pipe-   43 protection cap-   200 sealing element-   202 sealing element-   210 peripheral bead-   300 connection section-   305 a protrusions-   301 fluid conduit-   310 outer pipe-   400 septum hood-   401 cover-   403 detent lug-   405 sealing edge-   500 blood treatment apparatus

1-16. (canceled)
 17. A medical fluid coupling configured to be connectedto a connection section of a blood treatment apparatus or of aconnecting adapter, the fluid coupling comprising: a main bodycomprising: a receiving section configured for connecting to a fluidconduit of the connection section; and a first latching element having afirst section that is elastically bendable or elastically tiltable, thefirst latching element comprising at least one of: (i) a recess forreceiving a protrusion of the connection section and (ii) an elevationto reach into a recess of the blood treatment apparatus or of theconnecting adapter, wherein the recess or the elevation either faces thereceiving section, or is arranged at the inner side of the firstlatching element, or both.
 18. The fluid coupling of claim 17, whereinthe main body further comprises a second latching element having asecond section that is elastically bendable or elastically tiltable. 19.The fluid coupling of claim 18, wherein the first section of the firstlatching element and the second section of the second latching elementare, in a non-connected state, arranged having a first distance betweeneach other, and wherein, during the process of connecting the fluidcoupling to the connection section, the first space becomes a seconddistance which is larger than the first distance.
 20. The fluid couplingof claim 18, wherein at least one of the first section of the firstlatching element and the second section of the second latching elementis designed as a tiltable section or is arranged at a further section ofthe respective latching elements in a tiltable manner.
 21. The fluidcoupling of claim 17, wherein the main body defines a fluid guidingsection therethrough, and wherein an inner diameter of the fluid guidingsection remains constant and is between 4.0 and 4.5 mm.
 22. The fluidcoupling of claim 17, wherein the main body is made of or comprises afirst material, and wherein the fluid coupling comprises at least onesealing element made of a second material which is different from thefirst material.
 23. The fluid coupling of claim 22, wherein the mainbody defines a fluid guiding section, and wherein the sealing elementcomprises a through opening having at least one inner diameter whichcorresponds to an inner diameter of the fluid guiding section.
 24. Thefluid coupling of claim 17, wherein the main body defines a fluidguiding section therethrough having a first end area, a second end area,and at least one further opening which is closed by a septum.
 25. Thefluid coupling of claim 17, wherein the main body defines a fluidguiding section as a main canal with a lumen for guiding a first fluidthrough the fluid coupling and defines a secondary canal with asecondary canal outlet for adding a second fluid into the main canal,wherein the fluid coupling comprises an actuating element arrangedrelative to the main body to be movable between a first position and asecond position, and wherein the fluid coupling comprises a sealingsection which is twistable, by movements of the actuating element,between: (i) a first position of the sealing section in which thesealing section does not close or cover the secondary canal outlet and(ii) a second position of the sealing section in which the sealingsection closes or covers the secondary canal outlet.
 26. A system,comprising: a fluid coupling; and a connection section of a bloodtreatment apparatus or of a connecting adapter, wherein the fluidcoupling comprises a main body comprising: a receiving sectionconfigured for connecting to a fluid conduit of the connection section;and a first latching element having a first section that is elasticallybendable or elastically tiltable, the first latching element comprisingat least one of: (i) a recess for receiving a protrusion of theconnection section and (ii) an elevation to reach into a recess of theblood treatment apparatus or of the connecting adapter, wherein therecess or the elevation either faces the receiving section, or isarranged at the inner side of the first latching element, or both, andwherein fluid coupling and connection section are designed and providedto be latched together in a latching connection.
 27. The system of claim26, wherein the main body defines a fluid guiding section therethrough,wherein an inner diameter of the fluid guiding section and an innerdiameter of a fluid conduit of the connection section are the same in anarea of a front face assigned to or facing the fluid guiding section.28. The system of claim 27, wherein the inner diameter of the fluidguiding section, an inner diameter of a sealing element, and the innerdiameter of the fluid conduit are the same in the area of the front faceassigned to or facing the fluid guiding section.
 29. The system of claim26, further comprising the blood treatment apparatus comprising theconnection section.
 30. The system of claim 26, further comprising atube line connected to the fluid coupling.
 31. The system of claim 30,wherein a length of the tube line is 100 mm maximally.
 32. The system ofclaim 26, further comprising a blood treatment machine connected influid communication to the blood treatment apparatus or with theconnecting adapter.